The Anschutz Medical Campus (AMC) at University of Colorado Denver (UC Denver) is one of the foremost and newest biomedical research centers in the country and is the largest center for biomedical research between Chicago, Texas, and the West Coast. The animal program at the UC Denver plays an important role in facilitating basic and translational research. The Universities research principal investigators have been diligent and successful in obtaining funding to support an ever expanding research enterprise on the new campus. This has resulted in an increase in the amount of funding to $412 million in Fiscal Year 2010, which represents a 16% increase over 2007 levels, or approximately 4% per year. This is a significant accomplishment in an era of shrinking research budgets and highly competitive funding. Since the new vivarium facilities opened at the AMC in January of 2004, the average daily census has increased by almost 55%. With the addition of the R2 vivarium in the fall of 2008, the University has planned for square footage to accommodate the growing research need at the University for the next several years, however, even with the significant investment into the animal program, there was a limit to the amount of funds available to complete the R2 vivarium project. As a result of project budget cutbacks, many of the racks, caging and supplies required to ensure maximum housing capacity in the R2 vivarium were not purchased on the initial project budget. Instead, a decision was made to purchase this equipment as the census numbers in the R2 facility grew. Unfortunately, the budget situation in the State of Colorado has significantly worsened over the past two years resulting in major cutbacks to Higher Education and ultimately the University of Colorado. Due to the increasing success of our principal investigators in attracting funding for research at the University, as well as high level successful recruitment efforts, the growth in the census of animals is only expected to continue to increase at a high rate. This growth will continue to cause an increased demand on the limited resources of our animal program. This application focuses on the purchase of 32 single-sided high density ventilated cage racks and turn around caging for the R2 vivarium. This equipment will provide additional housing capacity for 2,240 more cages, or an approximately 20% increase in housing capacity at the R2 vivarium helping to accommodate a growth rate of at least 5 % per year that is anticipated based on historical growth. This will have a significant positive impact for the Principal Investigators that house their mice in the R2 vivarium, allowing them to remain competitive for grants without having to limit their research effort. The high density ventilated cage racks requested in this application were designed for in the original building plans and will be hard-ducted to existing room level blowers already in place and balanced to the room. The ventilated cage racks will also be attached to existing automatic watering drops. Therefore, no renovations are requested in this application to accommodate these high density ventilated cage racks.